Lecture 1-3

Question 1

Lecture 1: What is the process of Gastrulation?

Answer 1

Process where the embryo forms from blastula to germ layers —> ectoderm, mesoderm, endoderm

Question 2

Lecture 1: What is the process of Neurulation?

Answer 2

Cells within ectoderm form the neural plate —> neural plate forms floor plate, roof plate and neural crest

Question 3

Lecture 1: What is the process of formation of brain in early embryosis?

Answer 3

Gastrulation —> Neurulation —> neural plate —> neural tube
- in neural tube formation, somites in mesoderm acts as precursors for muscular and skeletal formation
- in neural tube consists of multipotent neural precursor cells and radial cells

Question 4

Lecture 1: What is Retinoic acid (RA)?

Answer 4

Drives cellular differentiation by binding to Retinoic receptors to interact with transcription co-factors modulating gene expression in early embryogenesis
- Vitamin A excess or deficiency = birth death by malformation of neural tube

Question 5

Lecture 1: What is Fibroblast Growth Factors (FGFs)?

Answer 5

Bind to receptor tyrosine kinase to activate ras-MAP kinase pathway
- FGF8 important for forebrain and midbrain development

Question 6

Lecture 1: What are BMPs?

Answer 6

Released by roofplate for bone development and differentiation of dorsal spinal cord, hind brain and cerebral cortex
- if expressed = forms epidermis
- if not expressed (by noggin and chordin) = form neuroectoderm

Question 7

Lecture 1: What is Wnts?

Answer 7

2 Pathways:
Canonical Pathway: induces gene expression by activating Frizzled receptor and stabilization of β-catenin—> interaction w/ transcription factors in nucleus
Non-Canonical Pathway: regulates cell movement and fate of lengthening neural plate/tube via activation of Frizzled and changes to Ca2+ and protein kinase C in intracellular membrane

Question 8

Lecture 1: What is Sonic Hedgehog (Shh)?

Answer 8

Acts on patched and smoothed surface receptors to translocate Gil1/Gil2 into nucleus for the differentiation of neurons within ventral spinal cord (motor neurons)
- if not expressed = inhibition = Gil3 represses expression of target genes

Question 9

Lecture 1: What is the effect of all the Inductive Signals working together?

Answer 9

Creates gradients to regulate neural tube formation & differentiation during different phases of development —> spinal cord signals can induce or inhibit gene expression by expressing different levels of gene expression

Question 10

Lecture 1: What are Stem Cells?

Answer 10

Can be manipulated to become a different identity of another cell
- SHinya Yamanaka created Induced Pluripotent Stem (iPS) cells from Fibroblasts in 2006, using 3/4 retroviruses

Question 11

Lecture 1: What is the Delta-Notch process?

Answer 11

Involves interaction of transmembrane ligands (Dleta) and surface receptors (Notch) to induce expression of neurogenic factors basic helix-loop-helix (bHLH) as well as regulate generation of glial cells
- when bound, notch intracellular domain (NICD) cleaves/translocates to nucleus to interact with transcription factors

Question 12

Lecture 1: Overview of the process of Inductive Signals.

Answer 12

Question 13

Lecture 1: Discuss the importance and process of a Migratory Path.

Answer 13

• migratory path of cells helps to regulate final position and identity of postmiotic cells
• migratory path of neural crest cells are first influenced by anterior (rostral) - posterior (caudal) position in neural tube

Question 14

Lecture 1: Describe the migratory pathway for Neural Crest cells (NCCs).

Answer 14

• NCCs start as neuroectodermal cells, undergoing an epithelial to migratory transition
• NCCs upregulate Snail 1 and 2 to inhibit protein expression and cellular adhesion
• NCCs are attracted in the periphery (mesodermal layer) by somites
• NCCs follow distinct paths to help distinguish finial position and identity

Question 15

Lecture 1: What are the neuronal population that are specialized?

Answer 15

Unipolar sensory neurons —> dorsal root ganglia of peripheral nervous system

Chromaffin cells —> adrenal medulla of the adrenal gland

Autonomic neurons —> cranial nerves, sympathetic chain, and autonomic ganglia

Question 16

Lecture 1: What is considered the “small brain”?

Answer 16

Neural crest —> enteric nervous system —> regulating gut motility, digestion, and immune function
- disrupts migration of NCCs —> digestive syndromes (Hirshprung’s disease)

Question 17

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Question 19

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Question 21

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